Etched Copper Mantle Clock

This is number three in this ‘class’ of clocks I’ve been making lately, the first one can be seen in my previous projects page.

First the general information:Overall the clock is 10”x10”, give or take. The clock guts are a KlockKit quartz movement. I like these movements because they are accurate, inexpensive, and small. A removable rear panel allows access for battery replacement and time setting. The dial is behind a glass pane, which also can be easily removed if needed.

The clock body is made from Walnut, the finish is blonde shellac.

The dial face is copper with etched inlaid numbers and a Celtic knot pattern.

My two previous clocks used segmented wood dials with copper rod used for the hour marks. The construction details for the Walnut dial face show how that gets made. This time I decided I wanted more copper. To me, copper and dark woods just go great together for some reason.

The face began life as a blank FR4 printed circuit board with 4 oz. copper on a single side. I’ve made plenty of printed circuit boards as a kid and I thought this would be the perfect way to get my copper fix.

The nice thing about using printed circuit techniques is you can get any pattern with any level of detail etched into copper (and other metals). For this clock face I used an Arts & Crafts font for the numbers and arranged them on a circle. The Celtic knot was an after thought, used more as a way to fill the design void on the dial but I really liked how it came out.

Anyhoo, a picture of this dial design was printed onto transparency film which was then used to create a photographic mask for the printed circuit board. After some UV light, chemistry, etchant, and sacrifices to the Tree Gods, I had exactly what I wanted. The etching removed all the copper down to the fiberglass backer. Normally this would be good enough, but the fiberglass had an ugly green/brown color and I wanted black. The solution was to fill the etched recesses with black enamel and then sand the entire surface to clear up the spill over. Basically I replaced the layer of copper with a layer of black enamel.

The last thing to do was to make the copper look old. There are 100’s of recipes for copper patina, but I went with the old standby of salt and vinegar.The final produce had a nice crusty blue-green variegation, but my wife grimaced when I showed it to her so I toned it down a tad (I’ll sneak in a nice crusty face in some future project).

Some spray satin poly to seal it all up, assemble the case, instant clock!

I’ve thought about detailing the making of the dial since it opens up a huge avenue for design elements. The knot itself is clipart, with some touchups in potential problem areas (usually a border between bands that is a touch to narrow).

In general, the photographic PC Board method works with any black/white line art. That art can either be a freehand sketch, a software drawing, or my favorite, manipulation with photo editing software. The end game is to have the drawing purely black/white, no grey. This is then printed onto overhead transparency film. I used a laser printer but I have read that an ink jet is actually a bit better.

It is true that one could just spray paint the design on a sheet of copper using a stencil or apply it free hand, but having it etched into the surface is so much better. Making a stencil is actually more work than the photographic process, and you have to deal with ‘islands’, those bits like the center of the number ‘zero’ that would fall away unless connection bars are left in the design. Freehand painting is perfectly fine if you have an artistic hand (which I don’t).Etching lets me create exactly what I want, make it any color I want, and still leave the copper available for a patina or any other treatment where the chemicals used might not play nice with a design painted onto the copper surface.

This is really neat! I do coppersmithing and woodworking, and like to combine them as well…in spite of not posting them on my projects page, I have a considerable amount. I’m not clear on the Celtic knot part. It appears as though the loop at the 6 o’clock mark is offset. Is this an artifact of camera offset? Don’t get me wrong, I’m not complaining- my camera skills (actually, the lack thereof) are why I have only posted a couple of things.

This is really neat! I do coppersmithing and woodworking, and like to combine them as well…in spite of not posting them on my projects page, I have a considerable amount. I m not clear on the Celtic knot part. It appears as though the loop at the 6 o clock mark is offset. Is this an artifact of camera offset? Don t get me wrong, I m not complaining- my camera skills (actually, the lack thereof) are why I have only posted a couple of things.

- Dark_Lightning

Most of what you see is a combination of camera offset and the illusion of the hour hand being slightly rotated (It is 10 past 6 after all 8^)

I will admit there is a slight (1/8”) offset (side to side) between the center of the face and the center of the clock shaft due to issues aligning the numbers around the circle.